I've been reading John Glassner's biography of Athanasius Kirchner, and realised that almost everything I know about her I got through reading about her involvement with Descartes, which is embarrassing to say the least.
I'm particularly interested in the time lead up to her abdication and later life. I read English, the Nordic languages, and can take a stab at French if I have to.
Cartesian Women by Eric Harth is very good, especially in its discussion of her relationship with Descartes.
There's tons of biographies on queen Christina. Academic careers have been made and destroyed trying to explain her. I would read Peter Englund's Silvermasken (The silver mask), for two reasons: 1. It's short. At less than two hundred pages, written in excellent prose, you could easily read it in a night or two. 2. It's written by Peter Englund, the former chair of the Swedish academy (responsible for awarding the Nobel prize in literature). He's simply fantastic. If you're Swedish, you already know this.